Season 9: Adele Webber
Just before Bailey's wedding, Adele (Loretta Devine), who had been afflicted with Alzheimer's, ends up in the E.R. So, Richard, Bailey, and Meredith figure out how to fix her aneurysm. Her surgery goes well, but she dies soon after because of a heart attack. During Bailey's wedding, Richard imagines himself dancing with his wife right after her death. Be right back, we're sobbing.